Internal combustion engines generate exhaust as a by-product of fuel combustion within the engines. Engine exhaust contains, among other things, un-burnt fuel, particulate matter such as soot, and harmful gases such as carbon monoxide or nitrous oxide. To comply with regulatory emissions control requirements, it is desirable to reduce the amount of soot and harmful gases generated by the engine.
One technique for reducing the production of harmful emissions in an engine consists of expelling a majority of the residual gases from the combustion chamber during scavenging. Expelling the majority of residual gases from the combustion chamber allows a cooler intake charge of air with a higher oxygen concentration to be used for the next combustion cycle. This results in improved combustion, which produces smaller amounts of soot and lower concentrations of carbon monoxide and nitrous oxide gases.
U.S. Pat. No. 4,353,333 B2 to Iio. (“the '333 patent”) describes the use of two auxiliary ports located on either side of a single intake port in a two cycle engine. The auxiliary ports serve to increase the area through which air can enter a combustion chamber during scavenging. The two auxiliary ports of the '333 patent have a smaller width along the circumference compared to the primary intake port, and have heights about equal to that of the primary intake port.
Although the '333 patent discloses the use of additional ports to improve scavenging, merely adding two ports may not be sufficient to meet the emissions standards applicable to modern engines. Moreover, the number of intake ports which can be added to an engine cylinder may be limited by the circumferential surface area available on the cylinder. In addition, merely adding auxiliary ports as disclosed by the '333 patent may not help to achieve a uniform temperature in the combustion chamber after scavenging.
The cylinder liner of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.